In forensic science, questioned document examination (QDE) is the examination of documents potentially disputed in a court of law. Its primary purpose is to provide evidence about a suspicious or questionable document using scientific
processes and methods. Evidence might include alterations, the chain of
possession, damage to the document, forgery, origin, authenticity, or
other questions that come up when a document is challenged in court.

Many QD examinations involve a comparison of the questioned document,
or components of the document, to a set of known standards. The most
common type of examination involves handwriting wherein the examiner
tries to address concerns about potential authorship.

A document examiner is often asked to determine if a questioned item
originated from the same source as the known item(s), then present their
opinion on the matter in court as an expert witness. Other common tasks
include determining what has happened to a document, determining when a
document was produced, or deciphering information on the document that
has been obscured, obliterated, or erased.

The discipline is known by many names including 'forensic document examination', 'document examination', 'diplomatics',
'handwriting examination', or sometimes 'handwriting analysis',
although the latter term is not often used as it may be confused with graphology. Likewise a forensic document examiner (FDE) is not to be confused with a graphologist, and vice versa.

Many FDEs receive extensive training in all of the aspects of the
discipline. As a result, they are competent to address a wide variety of
questions about document evidence. However, this "broad specialization"
approach has not been universally adopted.

In some locales, a clear distinction is made between the terms
'forensic document examiner' and a 'forensic handwriting
expert/examiner'. In such cases, the former term refers to examiners who
focus on non-handwriting examination types while the latter refers to
those trained exclusively to do handwriting examinations. Even in places
where the more general meaning is common, such as North America or
Australia, there are many individuals who have specialized training only
in relatively limited areas. As the terminology varies from
jurisdiction to jurisdiction, it is important to clarify the meaning of
the title used by any individual professing to be a "forensic document
examiner".

A forensic document examiner is intimately linked to the legal system as a forensic scientist. Forensic science is the application of science to address issues under consideration in the legal system. FDEs examine items (documents) that form part of a case that may or may not come before a court of law.